Effects of High Pressure on Bacteria and Fungi

Abstract

Microorganisms are killed by high hydrostatic pressure. This pressure-induced inactivation is strongly dependent on the amount of applied pressure, the temperature, and the medium. Bacteria and fungi show some typical differences in their behavior in response to pressure. Here, the kinetics of inactivation of fungal spores, the pressure resistant part of fungi, is described. These spores reveal a special kind of stability against pressure, which presents a potential source of trouble in food processing. Experiments using dyes and electron microscopy give some hints to the mechanism of pressure inactivation of bacteria. It seems that the bacterial membrane plays a major role during the inactivation process.